Conventionally, a container set in which a plurality of containers are connected by a package sheet or a paper tray is well known, for facilitating carriage of the plurality of containers or clarifying the relationships among the plurality of containers. As such a container set, there are known a structure in which containers that are individually covered with a package sheet in advance are connected by means of a separate member such as a paper tray, and a structure in which the package sheets covering the containers are connected to each other. In the former case, there is an advantage that the structure can be applied to containers of various shapes, but the separate member such as the paper tray must be provided in addition to the package sheet, and, thus, there is a problem of increased cost and labor.
In the latter case, because the separate member such as the paper tray does not need to be provided, cost and labor may be saved. Such a type of the container set is disclosed in, for example, below-described Patent Literature 1-4. The container set of Patent Literature 1 is constructed by covering, on each container, each of a plurality of heat-shrinkable sleeves which are connected to each other, and heating the structure in this state to cause the heat-shrinkable sleeve to shrink. The container sets of Patent Literature 2-4 are constructed by covering the respective containers with tubular sheet members which are connected to each other.